when i first got to tier 3 I thought that the enemies learn a couple new things and are more annoying to kill NOPE the new moves were hard to deal with and the enemies hit like a truck so i play on advanced and its still a fun challenge which was what the game kinda lacked while i was up to date in tier 1 and 2
Adding to beemomasters comment you kill greys by tricking them into firing their spike ad hitting them before they retract it. During the period it is out they are soft.
monnmonn i agree the balloons don't have a single weapon and they can't hold anything so do they just bump into monkeys or what do they do that is so monkey threatening